Electrical stimulation or functional electrical stimulation (FES) of muscles is a well-known application e.g. in the areas of stroke rehabilitation, spinal cord injury rehabilitation, incontinence treatment, and sport enhancement treatment.
From WO 2007/017778 A2, an apparatus for electrical stimulation of muscle tissue is known that has an electrode system with an electrode array. The apparatus has an electrode selector for selecting one or more stimulating electrode pads. In one example, after the electrode system is positioned on the skin of a user, the impedance between each of the electrode pads and the skin is measured, and based on the measured impedance, one or more stimulation electrode pads are selected. In another example, stimulation electrode pads may be selected based on the area in which the muscle exhibits the lowest activity. The apparatus may be used to stimulate the muscle tissue by providing an electrical signal such that the muscle tissue alternately contracts and relaxes. Prior to stimulating the muscle tissue, a first measurement of the activity of the muscle tissue is performed, and after stimulating the muscle tissue, a second measurement of the activity of the muscle tissue is performed. Thus, the effect of the stimulation on the activity of the muscle tissue can be determined. The values for the activity determined before and after the stimulation may be outputted to a user interface.